/**
* @file file_server.hpp
* @author zhaobohan (zhaobohan_free@163.com)
* @brief 构造文件服务的服务器，依赖于建造者模式
*/
#include <brpc/server.h>
#include <butil/logging.h>

#include "etcd.hpp"     // 服务注册模块封装
#include "logger.hpp"   // 日志模块封装
#include "utils.hpp"
#include "base.pb.h"
#include "file.pb.h"

namespace free_im {
class FileServiceImpl : public free_im::FileService
{
public:
    FileServiceImpl(const std::string &storage_path)
        : _storage_path(storage_path)
    {
        umask(0);
        mkdir(storage_path.c_str(), 0775);
        if (_storage_path.back() != '/') _storage_path.push_back('/');
    }

    ~FileServiceImpl()
    {}

    // 读取单个文件
    void GetSingleFile(google::protobuf::RpcController* controller,
                const ::free_im::GetSingleFileReq* request,
                ::free_im::GetSingleFileRsp* response,
                ::google::protobuf::Closure* done) 
    {
        brpc::ClosureGuard rpc_guard(done);
        response->set_request_id(request->request_id());
        // 1. 取出请求中的文件ID（起始就是文件名）
        std::string fid = request->file_id();
        std::string filename = _storage_path + fid;
        // 2. 将文件ID作为文件名，读取文件数据
        std::string body;
        bool ret = readFile(filename, body);
        if (ret == false) 
        {
            response->set_success(false);
            response->set_errmsg("读取文件数据失败！");
            LOG_ERROR("{} 读取文件数据失败！", request->request_id());
            return;
        }
        // 3. 组织响应
        response->set_success(true);
        response->mutable_file_data()->set_file_id(fid);
        response->mutable_file_data()->set_file_content(body);
    }

    // 读取多个文件
    void GetMultiFile(google::protobuf::RpcController* controller,
                const ::free_im::GetMultiFileReq* request,
                ::free_im::GetMultiFileRsp* response,
                ::google::protobuf::Closure* done) 
    {
        brpc::ClosureGuard rpc_guard(done);
        response->set_request_id(request->request_id());
        // 循环取出请求中的文件ID，读取文件数据进行填充
        for (int i = 0; i < request->file_id_list_size(); i++) 
        {
            std::string fid = request->file_id_list(i);
            std::string filename = _storage_path + fid;
            std::string body;
            bool ret = readFile(filename, body);
            if (ret == false) 
            {
                response->set_success(false);
                response->set_errmsg("读取文件数据失败！");
                LOG_ERROR("{} 读取文件数据失败！", request->request_id());
                return;
            }
            FileDownloadData data;
            data.set_file_id(fid);
            data.set_file_content(body);
            response->mutable_file_data()->insert({fid, data});
        }
        response->set_success(true);
    }

    // 写入单个文件
    void PutSingleFile(google::protobuf::RpcController* controller,
                const ::free_im::PutSingleFileReq* request,
                ::free_im::PutSingleFileRsp* response,
                ::google::protobuf::Closure* done) 
    {
        brpc::ClosureGuard rpc_guard(done);
        response->set_request_id(request->request_id());

        // 1. 为文件生成一个唯一uudi作为文件名 以及 文件ID
        std::string fid = uuid();
        std::string filename = _storage_path + fid;

        // 2. 取出请求中的文件数据，进行文件数据写入
        bool ret = writeFile(filename, request->file_data().file_content());
        if (ret == false)
        {
            response->set_success(false);
            response->set_errmsg("读取文件数据失败！");
            LOG_ERROR("{} 写入文件数据失败！", request->request_id());
            return;
        }

        //3. 组织响应
        response->set_success(true);
        response->mutable_file_info()->set_file_id(fid);
        response->mutable_file_info()->set_file_size(request->file_data().file_size());
        response->mutable_file_info()->set_file_name(request->file_data().file_name());
    }

    // 写入多个文件
    void PutMultiFile(google::protobuf::RpcController* controller,
                const ::free_im::PutMultiFileReq* request,
                ::free_im::PutMultiFileRsp* response,
                ::google::protobuf::Closure* done) 
    {
        brpc::ClosureGuard rpc_guard(done);
        response->set_request_id(request->request_id());
        for (int i = 0; i < request->file_data_size(); i++) 
        {
            std::string fid = uuid();
            std::string filename = _storage_path + fid;
            bool ret = writeFile(filename, request->file_data(i).file_content());
            if (ret == false) 
            {
                response->set_success(false);
                response->set_errmsg("读取文件数据失败！");
                LOG_ERROR("{} 写入文件数据失败！", request->request_id());
                return;
            }
            free_im::FileMessageInfo *info  = response->add_file_info();
            info->set_file_id(fid);
            info->set_file_size(request->file_data(i).file_size());
            info->set_file_name(request->file_data(i).file_name());
        }

        response->set_success(true);
    }

private:
    std::string _storage_path;
};

// 文件服务器
class FileServer 
{
public:
    using ptr = std::shared_ptr<FileServer>;
    FileServer(const Registry::ptr &reg_client,
        const std::shared_ptr<brpc::Server> &server):
        _reg_client(reg_client),
        _rpc_server(server)
    {}

    ~FileServer()
    {}

    // 搭建RPC服务器，并启动服务器
    void start() 
    {
        _rpc_server->RunUntilAskedToQuit();
    }

private:
    Registry::ptr _reg_client;
    std::shared_ptr<brpc::Server> _rpc_server;
};

// 建造文件服务器
class FileServerBuilder 
{
public:
    // 用于构造服务注册客户端对象
    void make_reg_object(const std::string &reg_host,
        const std::string &service_name,
        const std::string &access_host) 
    {
        _reg_client = std::make_shared<Registry>(reg_host);
        _reg_client->registry(service_name, access_host);
    }

    // 构造RPC服务器对象
    void make_rpc_server(uint16_t port, int32_t timeout, 
        uint8_t num_threads, const std::string &path = "./data/") 
    {
        _rpc_server = std::make_shared<brpc::Server>();
        FileServiceImpl *file_service = new FileServiceImpl(path);
        int ret = _rpc_server->AddService(file_service, 
            brpc::ServiceOwnership::SERVER_OWNS_SERVICE);
        if (ret == -1) 
        {
            LOG_ERROR("添加Rpc服务失败！");
            abort();
        }
        brpc::ServerOptions options;
        options.idle_timeout_sec = timeout;
        options.num_threads = num_threads;
        ret = _rpc_server->Start(port, &options);
        if (ret == -1) 
        {
            LOG_ERROR("服务启动失败！");
            abort();
        }
    }

    FileServer::ptr build() 
    {
        if (!_reg_client) 
        {
            LOG_ERROR("还未初始化服务注册模块！");
            abort();
        }
        if (!_rpc_server) 
        {
            LOG_ERROR("还未初始化RPC服务器模块！");
            abort();
        }

        FileServer::ptr server = std::make_shared<FileServer>(_reg_client, _rpc_server);
        return server;
    }

private:
    Registry::ptr _reg_client;
    std::shared_ptr<brpc::Server> _rpc_server;
};
}